Detection accuracy for epithelial dysplasia using an objective autofluorescence visualization method based on the luminance ratio

Effectiveness of adjunctive screening tools for potentially malignant oral disorders and oral cancer: A systematic review

Background and objectives

To enhance the abilities of healthcare professionals to make informed treatment decisions and establish accurate diagnoses, it is essential to assess the diagnostic reliability of different adjunctive aids. This systematic review aimed to compare the accuracy of various adjunctive methods for diagnosing suspected oral cancer (OC) or potentially malignant oral disorders (OPMD) in adults against histopathological investigative results.

Materials and methods

The review protocol registered in the PROSPERO database (CRD42023463525) was developed in strict accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis-Diagnostic Test Accuracy checklist. A comprehensive electronic search was conducted to identify relevant research articles published between January 2014 and April 2023 using the PubMed and EBSCO databases. The research question was meticulously structured following the participants' index test, reference standard, target condition, and study setting framework. To evaluate methodological quality and assess the risk of bias (RoB), the Quality Assessment for Diagnostic Accuracy Studies-2 tool was used.

Results

An initial search yielded 483 publications, which were reduced to 278 after removal of duplicates. Finally, 85 publications underwent full-text review by two investigators, which lead to 29 studies that met the inclusion criteria. Among these, 7% had a low RoB, 72% had an unclear RoB, and 21% had a high RoB. Applicability concerns were expressed in 59% of the studies with low concern, 31% with unclear quality evidence of concern, and 10% with high concern.

Conclusion

The review findings support the use of these diagnostic methods as valuable adjuncts to biopsy for the early detection of various OPMD and OC. They also highlight the importance of regular screening and awareness in reducing the global burden of OC, while acknowledging that they cannot replace the gold standards of surgical biopsy and histopathological evaluation.

Current advances in noninvasive methods for the diagnosis of oral squamous cell carcinoma: a review

Oral squamous cell carcinoma (OSCC), one of the most common types of cancers worldwide, is diagnosed mainly through tissue biopsy. However, owing to the tumor heterogeneity and other drawbacks, such as the invasiveness of the biopsy procedure and high cost and limited usefulness of longitudinal surveillance, there has been a focus on adopting more rapid, economical, and noninvasive screening methods. Examples of these include liquid biopsy, optical detection systems, oral brush cytology, microfluidic detection, and artificial intelligence auxiliary diagnosis, which have their own strengths and weaknesses. Extensive research is being performed on various liquid biopsy biomarkers, including novel microbiome components, noncoding RNAs, extracellular vesicles, and circulating tumor DNA. The majority of these elements have demonstrated encouraging clinical outcomes in early OSCC detection. This review summarizes the screening methods for OSCC with a focus on providing new guiding strategies for the diagnosis of the disease.

Applicability of autofluorescence and fluorescent probes in the trans-surgical of oral carcinomas: A systematic review

Oral cancer represents an important health problem, as it is the sixth most common type of cancer in the world and is associated with high rates of morbidity and mortality. The treatment considered the gold standard for this type of tumor is surgical resection with negative margins, with a distance of at least 5 mm from the tumor. This procedure is strongly associated with local control and disease-specific survival, however, in many cases, large amounts of healthy tissue are removed, resulting in surgical defects, compromising various functions and directly affecting the individual's quality of life. From this perspective, this systematic review aimed to evaluate the use of autofluorescence and fluorescent probes as potential adjuvant techniques to facilitate the delineation of surgical margins for oral cancers. A comprehensive search was performed in Pubmed, Scopus, Web of Science, LIVIVO, Embase, ProQuest Open Access Dissertations & Theses, Open Access Theses and Dissertations, and DART Europe databases, where 1948 articles were found. After the different stages of critical evaluation, 15 articles were selected, eligible for the inclusion criteria. Of these, 7 articles used autofluorescence, 7 used fluorescent probes and 1 article used both methods. As for autofluorescence, the most used device was the VELScope, and indocyanine green was the most used probe. Compared to histopathology, autofluorescence did not obtain significant and/or superiors results. In contrast to fluorescent probes that, most articles showed a good performance of margins during surgical resection, making them a promising alternative. However, it is still necessary to carry out the analysis of more articles, with more significant samples and sensitivity and specificity data to qualify the results.

Field validation of deep learning based Point-of-Care device for early detection of oral malignant and potentially malignant disorders

Early detection of oral cancer in low-resource settings necessitates a Point-of-Care screening tool that empowers Frontline-Health-Workers (FHW). This study was conducted to validate the accuracy of Convolutional-Neural-Network (CNN) enabled m(mobile)-Health device deployed with FHWs for delineation of suspicious oral lesions (malignant/potentially-malignant disorders). The effectiveness of the device was tested in tertiary-care hospitals and low-resource settings in India. The subjects were screened independently, either by FHWs alone or along with specialists. All the subjects were also remotely evaluated by oral cancer specialist/s. The program screened 5025 subjects (Images: 32,128) with 95% (n = 4728) having telediagnosis. Among the 16% (n = 752) assessed by onsite specialists, 20% (n = 102) underwent biopsy. Simple and complex CNN were integrated into the mobile phone and cloud respectively. The onsite specialist diagnosis showed a high sensitivity (94%), when compared to histology, while telediagnosis showed high accuracy in comparison with onsite specialists (sensitivity: 95%; specificity: 84%). FHWs, however, when compared with telediagnosis, identified suspicious lesions with less sensitivity (60%). Phone integrated, CNN (MobileNet) accurately delineated lesions (n = 1416; sensitivity: 82%) and Cloud-based CNN (VGG19) had higher accuracy (sensitivity: 87%) with tele-diagnosis as reference standard. The results of the study suggest that an automated mHealth-enabled, dual-image system is a useful triaging tool and empowers FHWs for oral cancer screening in low-resource settings.

Non-invasive imaging of oral potentially malignant and malignant lesions: A systematic review and meta-analysis

Non-invasive (NI) imaging techniques have been developed to overcome the limitations of invasive biopsy procedures, which is the gold standard in diagnosis of oral dysplasia and Oral Squamous Cell Carcinoma (OSCC). This systematic review and meta- analysis was carried out with an aim to investigate the efficacy of the NI-imaging techniques in the detection of dysplastic oral potentially malignant disorders (OPMDs) and OSCC. Records concerned in the detection of OPMDs, Oral Cancer were identified through search in PubMed, Science direct, Cochrane Library electronic database (January 2000 to October 2020) and additional manual searches. Out of 529 articles evaluated for eligibility, 56 satisfied the pre-determined inclusion criteria, including 13 varying NI-imaging techniques. Meta-analysis consisted 44 articles, wherein majority of the studies reported Autofluorescence (AFI-38.6%) followed by Chemiluminescence (CHEM), Narrow Band Imaging (NBI) (CHEM, NBI-15.9%), Fluorescence Spectroscopy (FS), Diffuse Reflectance Spectroscopy (DRS), (FS, DRS-13.6%) and 5aminolevulinic acid induced protoporphyrin IX fluorescence (5ALA induced PPIX- 6.8%). Higher sensitivities (Sen) and specificities (Spe) were obtained using FS (Sen:74%, Spe:96%, SAUC=0.98), DRS (Sen:79%, Spe:86%, SAUC = 0.91) and 5 ALA induced PPIX (Sen:91%, Spe:78%, SAUC = 0.98) in the detection of dysplastic OPMDs from non-dysplastic lesions(NDLs). AFI, FS, DRS, NBI showed higher sensitivities and SAUC (>90%) in differentiating OSCC from NDLs. Analysed NI-imaging techniques suggests the higher accuracy levels in the diagnosis of OSCC when compared to dysplastic OPMDs. 5 ALA induced PPIX, DRS and FS showed evidence of superior accuracy levels in differentiation of dysplastic OPMDs from NDLs, however results need to be validated in a larger number of studies.

A comprehensive review on LED-induced fluorescence in diagnostic pathology

Sensitivity, specificity, mobility, and affordability are important criteria to consider for developing diagnostic instruments in common use. Fluorescence spectroscopy has been demonstrating substantial potential in the clinical diagnosis of diseases and evaluating the underlying causes of pathogenesis. A higher degree of device integration with appropriate sensitivity and reasonable cost would further boost the value of the fluorescence techniques in clinical diagnosis and aid in the reduction of healthcare expenses, which is a key economic concern in emerging markets. Light-emitting diodes (LEDs), which are inexpensive and smaller are attractive alternatives to conventional excitation sources in fluorescence spectroscopy, are gaining a lot of momentum in the development of affordable, compact analytical instruments of clinical relevance. The commercial availability of a broad range of LED wavelengths (255-4600 nm) has opened up new avenues for targeting a wide range of clinically significant molecules (both endogenous and exogenous), thereby diagnosing a range of clinical illnesses. As a result, we have specifically examined the uses of LED-induced fluorescence (LED-IF) in preclinical and clinical evaluations of pathological conditions, considering the present advancements in the field.

A Systematic Review of Oral Biopsies, Sample Types, and Detection Techniques Applied in Relation to Oral Cancer Detection

Background: Early identification of the stage of oral cancer development can lead to better treatment outcomes and avoid malignant transformation. Therefore, this review aims to provide a comprehensive overview that describes the development of standardized procedures for oral sample collection, characterization, and molecular risk assessment. This can help investigators to choose the appropriate sampling method and downstream analyses for different purposes. Methods: This systematic review was conducted according to the PRISMA guidelines. Using both PubMed and Web of Science databases, four independent authors conducted a literature search between 15 and 21 June 2021. We used key search terms to broaden the search for studies. Non-conforming articles were removed using an EndNote-based and manual approach. Reviewers used a designed form to extract data. Results: This review included a total of 3574 records, after eliminating duplicate articles and excluding papers that did not meet the inclusion criteria. Finally, 202 articles were included in this review. We summarized the sampling methods, biopsy samples, and downstream analysis. The biopsy techniques were classified into tissue and liquid biopsy. The common sequential analysis of tissue biopsy includes histopathological examination such as H&E or IHC to identify various pathogenic features. Meanwhile, liquid samples such as saliva, blood, and urine are analyzed for the purpose of screening to detect mutations in cancer. Commonly used technologies are PCR, RT-PCR, high-throughput sequencing, and metabolomic analysis. Conclusions: Currently, tissue biopsies provide increased diagnostic value compared to liquid biopsy. However, the minimal invasiveness and convenience of liquid biopsy make it a suitable method for mass screening and eventual clinical adoption. The analysis of samples includes histological and molecular analysis. Metabolite analysis is rising but remains scarce.

Possible Action of Olaparib for Preventing Invasion of Oral Squamous Cell Carcinoma In Vitro and In Vivo

Despite recent advances in treatment, the prognosis of oral cancer remains poor, and prevention of recurrence and metastasis is critical. Olaparib is a PARP1 inhibitor that blocks polyADP-ribosylation, which is involved in the epithelial–mesenchymal transition (EMT) characteristic of tumor recurrence. We explored the potential of olaparib in inhibiting cancer invasion in oral carcinoma using three oral cancer cell lines, HSC-2, Ca9-22, and SAS. Olaparib treatment markedly reduced their proliferation, migration, invasion, and adhesion. Furthermore, qRT-PCR revealed that olaparib inhibited the mRNA expression of markers associated with tumorigenesis and EMT, notably Ki67, Vimentin, β-catenin, MMP2, MMP9, p53, and integrin α2 and β1, while E-Cadherin was upregulated. In vivo analysis of tumor xenografts generated by injection of HSC-2 cells into the masseter muscles of mice demonstrated significant inhibition of tumorigenesis and bone invasion by olaparib compared with the control. This was associated with reduced expression of proteins involved in osteoclastogenesis, RANK and RANKL. Moreover, SNAIL and PARP1 were downregulated, while E-cadherin was increased, indicating the effect of olaparib on proteins associated with EMT in this model. Taken together, these findings confirm the effects of olaparib on EMT and bone invasion in oral carcinoma and suggest a new therapeutic strategy for this disease.

Evaluation of autofluorescence visualization system in the delineation of oral squamous cell carcinoma surgical margins

INTRODUCTION

Delineating the margins of Oral squamous cell carcinoma (OSCC) is a critical step for optimaltumor resection. The aim of this study was to evaluate the accuracy of lesion surgical margin identification using autofluorescence visualization.

MATERIALS AND METHODS

Thirty patients with OSCC were included in this study. For each lesion, the fluorescence loss boundary was determined using VELscope before ablative surgical resection (with a 1.5-2cm safety margin) was performed. A total of 126 samples were obtained from 30 surgical specimens, each containing the tissue from the fluorescence loss boundary to surgical margin. The status of each sample was determined by oral pathologists and the staining intensities of Ki-67, E-cadherin, and Vimentin at the fluorescence loss boundary and surgical margin were evaluated by immunohistochemistry.

RESULTS

Fluorescence loss regions were identified in all patients. Of the 126 samples collected, HE staining identified 77 normal epithelia (61.1%), 26 mild dysplasia (20.6%), 17 severe dysplasia (13.4%) and 6 carcinomas in situ (4.9%). A significant correlation was found between the differentiation grade of tumor cells and the pathological status of the surgical marginal specimens (P<0.05). Forty-two of the 126 samples were randomly selected for further immunohistochemical staining. No significant differences were seen in Ki-67, E-cadherin, or Vimentin expression at the fluorescence loss boundary or surgical margin, however, the proteins' expression level was positively correlated with the degree of dysplasia (P<0.01).

CONCLUSION

Autofluorescence visualization has potential as a simple surgical margin setting device for OSCC and may help delineate the superficial area of OSCC with acceptable accuracy. However, when considering the inherent limitations of this system, we suggest that the approach should only be applied under certain conditions, such as when dealing with superficial, well-differentiated lesions.

Accuracy of autofluorescence and chemiluminescence in the diagnosis of oral Dysplasia and Carcinoma: A systematic review and Meta-analysis

OBJECTIVES

To define the accuracy of autofluorescence-based (AF) and chemiluminescence-based (CL) systems in the diagnosis of oral dysplastic and malignant lesions in addition to the Conventional Oral Examination (COE).

MATERIALS AND METHODS

The study was performed according to the PRISMA-DTA guidelines.

RESULTS

A total of 2631 oral cavity lesions (AF, n = 2076; CL, n = 555) from 26 studies (AF = 17; CL = 9) was used for calculation of diagnostic accuracy parameters. The overall pooled sensitivity and specificity of the AF were 81.3% (95% CI: 74.3% - 87.5%) and 52.1% (95% CI: 36.9% - 67.1%), respectively. Cumulative diagnostic odds ratio (DOR) was 5.44 (95% CI: 2.29 - 10.56) with a significant heterogeneity between studies (I² = 80.7%, 95% CI: 70.0% - 86.7%; p < .05). The overall pooled sensitivity and specificity for the CL were 84.9% (95% CI: 66.7% - 96.7%) and 51.8% (95% CI: 37.3% - 65.9%), respectively. The overall pooled DOR was 8.59 (95% CI: 2.11 - 22.38) with a significant heterogeneity between studies (I² = 65.4%, 95% CI: 29.6% - 83.0%; p < .05).

CONCLUSIONS

AF and CL present a high sensitivity in the diagnosis of dysplastic and malignant oral cavity lesions, demonstrating that diagnostic biopsies may be avoided in case of a negative test result. Both tests have a low specificity, and the reduction of the false positive rate compared to the COE alone remains poor.

Diagnostic tests for oral cancer and potentially malignant disorders in patients presenting with clinically evident lesions

BACKGROUND

Squamous cell carcinoma is the most common form of malignancy of the oral cavity, and is often proceeded by oral potentially malignant disorders (OPMD). Early detection of oral cavity squamous cell carcinoma (oral cancer) can improve survival rates. The current diagnostic standard of surgical biopsy with histology is painful for patients and involves a delay in order to process the tissue and render a histological diagnosis; other diagnostic tests are available that are less invasive and some are able to provide immediate results. This is an update of a Cochrane Review first published in 2015.

OBJECTIVES

Primary objective: to estimate the diagnostic accuracy of index tests for the detection of oral cancer and OPMD, in people presenting with clinically evident suspicious and innocuous lesions.

SECONDARY OBJECTIVE

to estimate the relative accuracy of the different index tests.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: MEDLINE Ovid (1946 to 20 October 2020), and Embase Ovid (1980 to 20 October 2020). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were also searched for ongoing trials to 20 October 2020. No restrictions were placed on the language or date of publication when searching the electronic databases. We conducted citation searches, and screened reference lists of included studies for additional references.

SELECTION CRITERIA

We selected studies that reported the diagnostic test accuracy of the following index tests when used as an adjunct to conventional oral examination in detecting OPMD or oral cavity squamous cell carcinoma: vital staining (a dye to stain oral mucosa tissues), oral cytology, light-based detection and oral spectroscopy, blood or saliva analysis (which test for the presence of biomarkers in blood or saliva).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance. Eligibility, data extraction and quality assessment were carried out by at least two authors, independently and in duplicate. Studies were assessed for methodological quality using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Meta-analysis was used to combine the results of studies for each index test using the bivariate approach to estimate the expected values of sensitivity and specificity.

MAIN RESULTS

This update included 63 studies (79 datasets) published between 1980 and 2020 evaluating 7942 lesions for the quantitative meta-analysis. These studies evaluated the diagnostic accuracy of conventional oral examination with: vital staining (22 datasets), oral cytology (24 datasets), light-based detection or oral spectroscopy (24 datasets). Nine datasets assessed two combined index tests. There were no eligible diagnostic accuracy studies evaluating blood or salivary sample analysis. Two studies were classed as being at low risk of bias across all domains, and 33 studies were at low concern for applicability across the three domains, where patient selection, the index test, and the reference standard used were generalisable across the population attending secondary care. The summary estimates obtained from the meta-analysis were: - vital staining: sensitivity 0.86 (95% confidence interval (CI) 0.79 to 0.90) specificity 0.68 (95% CI 0.58 to 0.77), 20 studies, sensitivity low-certainty evidence, specificity very low-certainty evidence; - oral cytology: sensitivity 0.90 (95% CI 0.82 to 0.94) specificity 0.94 (95% CI 0.88 to 0.97), 20 studies, sensitivity moderate-certainty evidence, specificity moderate-certainty evidence; - light-based: sensitivity 0.87 (95% CI 0.78 to 0.93) specificity 0.50 (95% CI 0.32 to 0.68), 23 studies, sensitivity low-certainty evidence, specificity very low-certainty evidence; and - combined tests: sensitivity 0.78 (95% CI 0.45 to 0.94) specificity 0.71 (95% CI 0.53 to 0.84), 9 studies, sensitivity very low-certainty evidence, specificity very low-certainty evidence.

AUTHORS' CONCLUSIONS

At present none of the adjunctive tests can be recommended as a replacement for the currently used standard of a surgical biopsy and histological assessment. Given the relatively high values of the summary estimates of sensitivity and specificity for oral cytology, this would appear to offer the most potential. Combined adjunctive tests involving cytology warrant further investigation. Potentially eligible studies of blood and salivary biomarkers were excluded from the review as they were of a case-control design and therefore ineligible. In the absence of substantial improvement in the tests evaluated in this updated review, further research into biomarkers may be warranted.

Evaluation of oral potentially malignant disorders with autoflorescence, reflectance spectroscopy and vital staining and their correlation with histopathology - Hospital based prospective study

OBJECTIVES

To evaluate diagnostic efficacy of Identafi® and toluidine blue in screening of Oral Potentially Malignant Disorders (OPMDs).

MATERIALS AND METHODS

Forty nine patients (63 lesions) with OPMDs visiting Department of Oral Medicine and Radiology, B.P.Koirala Institute of Health Science (BPKIHS) were included in the study. After thorough history and oral examination, screening was done by Identafi® followed by toluidine blue staining. Then incisional biopsy under local anesthesia was performed from the site showing positive change followed by histopathological examination.

RESULTS

The overall sensitivity and specificity of Identafi®^'s violet light was 73% and 46.2%. The overall sensitivity and specificity of Identafi®^'s green-amber light were 78.4% and 15.4% respectively. The overall sensitivity and specificity of toluidine blue were 51.4 and 84.6 respectively. A statistically-significant association was observed between the toluidine blue and histopathology results, (p = 0.04), p value set at ≤ 0.05.

CONCLUSION

Identafi®'s violet light and green amber light are more sensitive in detecting true positives. Toluidine blue is highly specific in ruling out true negative cases. The screening of OPMDs will help in selecting proper biopsy site followed by early diagnosis and intervention, hence increasing the prognosis, outcome and decrease complications associated with it.

Management of oral leukoplakia: a position paper of the Society of Oral Medicine, Chinese Stomatological Association

OBJECTIVE

The objective of this study was to develop the first edition of a Chinese evidence-based position paper on the management of oral leukoplakia (OLK).

STUDY DESIGN

The consultant group for drafting the position paper consisted of 31 oral medicine specialists and 2 evidence-based medicine specialists. English studies (searched in PubMed, EMBASE, and the Cochrane Library) and Chinese studies (searched in China National Knowledge Infrastructure and WanFang) published before January 2018 were used. The quality of the study was assessed using the Grading of Recommendations Assessment, Development, and Evaluation grid, and the strength of the recommendations was determined based on the results of 3 rounds of voting among the consultant group members using the Delphi method.

RESULTS

Twenty-two evidence-based guidelines for clinical management and monitoring of OLK were established in this position paper. A clinical path diagram for oral health practitioners was constructed based on the recommendations.

CONCLUSION

Current evidence suggests that management and monitoring of patients with OLK should be performed by experienced clinicians to control the lesion and for early detection of malignant transformation. However, all recommendations are based on evidence of low or extremely low quality and may require further modification as new evidence is produced.

Clinicopathological Features Associated with Fluorescence Alteration: Analysis of 108 Oral Malignant and Potentially Malignant Lesions

Background: Several noninvasive diagnostic tools have been developed to aid the early detection of oral cancer and for evaluation before definitive biopsy. Among these, devices evaluating a tissues autofluorescence (AF) are emerging. In particular, the most well known of these is the VELscope^® system (LED Medical Diagnostics, Inc., Barnaby, Canada), which emits a light of 400-460 nm. This study has been developed to describe the most relevant clinicopathological features associated with AF alterations in a set of patients with oral squamous cell carcinoma and potentially malignant disorders (PMDs). Materials and methods: Overall, 108 lesions from 60 patients with clinical diagnoses of potentially malignant oral disorders and carcinomas were included in the study. For each case, the following variables were recorded and compared with the AF pattern: (1) clinical appearance (white, red, and white/red); (2) histological diagnosis (no dysplasia, mild/moderate dysplasia, severe dysplasia/in situ carcinoma, invasive carcinoma, and verrucous carcinoma); and (3) clinicopathological diagnosis. Binomial logistic regression was performed to investigate whether clinical appearance and/or histological diagnosis were significant in determining the degree of AF. Results: Among the white lesions, 66% resulted in hyper-fluorescence, whereas the red lesions appeared hypo-fluorescent in 95.2% of cases. The AF was altered (both hypo-fluorescent and hyper-fluorescent) in 36% of lesions without dysplasia; in 75.9% of lesions with mild or moderate dysplasia and in the totality of the in situ, invasive, and verrucous carcinomas (p < 0.0001). With regard to the binomial logistic regression, variables were separately considered and both were extremely significant in determining the degree of AF. Conclusions: Promising evidence for the use of AF as an adjunctive tool to conventional oral examinations (COEs) has been demonstrated. However, although the sensitivity of AF examination associated with COE is very high, both the literature and this study agree to indicate a low specificity.

Non-Invasive Diagnostic System Based on Light for Detecting Early-Stage Oral Cancer and High-Risk Precancerous Lesions-Potential for Dentistry

Simple Summary

The early detection of oral cancer and oral potentially malignant disorders can facilitate minimum intervention and subsequent improvements in prognosis and quality of life after treatment. Recently, several non-invasive adjunctive fluorescence-based detection systems have improved the accuracy of detection and diagnosis of oral cancer and oral potentially malignant disorders. This article summarizes current knowledge about fluorescence-based diagnostic methods and discusses their benefits and drawbacks from a clinical viewpoint.

Abstract

Oral health promotion and examinations have contributed to the early detection of oral cancer and oral potentially malignant disorders, leading to the adaptation of minimally invasive therapies and subsequent improvements in the prognosis/maintenance of the quality of life after treatments. However, the accurate detection of early-stage oral cancer and oral epithelial dysplasia is particularly difficult for conventional oral examinations because these lesions sometimes resemble benign lesions or healthy oral mucosa tissues. Although oral biopsy has been considered the gold standard for accurate diagnosis, it is deemed invasive for patients. For this reason, most clinicians are looking forward to the development of non-invasive diagnostic technologies to detect and distinguish between cancerous and benign lesions. To date, several non-invasive adjunctive fluorescence-based detection systems have improved the accuracy of the detection and diagnosis of oral mucosal lesions. Autofluorescence-based systems can detect lesions as a loss of autofluorescence through irradiation with blue-violet lights. Photodynamic diagnosis using 5-aminolevulinic acid (ALA-PDD) shows the presence of very early oral cancers and oral epithelial dysplasia as a red fluorescent area. In this article, currently used fluorescence-based diagnostic methods are introduced and discussed from a clinical point of view.

Histopathological determinants of autofluorescence patterns in oral carcinoma

Biological tissues (including oral mucosa) can absorb and re-emit specific light wavelengths, detectable through spectrophotometric devices. Such a phenomenon is known as "autofluorescence" (AF). Several devices evaluating tissue AF have been developed and commercialized in the last two decades. Among these, the VELscope® system has been proposed as a visual diagnostic aid for potentially malignant disorders and malignant lesions of the oral mucosa. In the present pilot study, we investigated which are the main histopathological features possibly related to variations in AF patterns in a set of 20 oral squamous cell verrucous carcinoma. Among all the histological features investigated, only the mean width of keratin was significantly different between hypofluorescent and hyperfluorescent carcinomas. The results of the present study demonstrate that AF features of oral malignant lesions are significantly associated with the width of their keratin layer.

Usefulness of fluorescence visualization-guided surgery for early-stage tongue squamous cell carcinoma compared to iodine vital staining

BACKGROUND

In the most cases of oral squamous cell carcinoma (OSCC), oral epithelial dysplasia (OED) is found adjacent to the primary tumor. The delineation of surgical margins for OSCC is critical to minimize the risk for local recurrence. The aim of this study is to demonstrate that the fluorescence visualization (FV)- device can delineated the lesion visualizes OED of adjacent primary tumors by histopathologically comparison to conventional iodine vital staining.

MATERIAL AND METHODS

The study involved 40 patients with superficial tongue squamous cell carcinoma treated from July 2016 to July 2018 at the Oral Cancer Center, Tokyo Dental College.

RESULTS

Cytokeratin 13 (CK13) expression rate in the area of fluorescence visualization loss (FVL) was significantly lower than that in the area of fluorescence visualization retention (FVR). In addition, CK17, Ki-67, and p53 expression rates were significantly higher in FVL than FVR. There was no significant difference in the delineation rate or area between FVL and iodine-unstained area. High-grade dysplasia was observed most frequently at the FV and iodine-unstained boundary, but no significant pathological differences were found.

CONCLUSION

We strongly suggest the FV-guided surgery is a useful method for accurate resection in early-stage tongue squamous cell carcinoma.

Spontaneous Development of Dental Dysplasia in Aged Parp-1 Knockout Mice

Poly(ADP-ribose) polymerase (Parp)-1 catalyzes polyADP-ribosylation using NAD⁺ and is involved in the DNA damage response, genome stability, and transcription. In this study, we demonstrated that aged Parp-1^-/- mouse incisors showed more frequent dental dysplasia in both ICR/129Sv mixed background and C57BL/6 strain compared to aged Parp-1^+/+ incisors, suggesting that Parp-1 deficiency could be involved in development of dental dysplasia at an advanced age. Computed tomography images confirmed that dental dysplasia was observed at significantly higher incidences in Parp-1^-/- mice. The relative calcification levels of Parp-1^-/- incisors were higher in both enamel and dentin (p < 0.05). Immunohistochemical analysis revealed (1) Parp-1 positivity in ameloblasts and odontoblasts in Parp-1^+/+ incisor, (2) weaker dentin sialoprotein positivity in dentin of Parp-1^-/- incisor, and (3) bone sialoprotein positivity in dentin of Parp-1^-/- incisor, suggesting ectopic osteogenic formation in dentin of Parp-1^-/- incisor. These results indicate that Parp-1 deficiency promotes odontogenic failure in incisors at an advanced age. Parp-1 deficiency did not affect dentinogenesis during the development of mice, suggesting that Parp-1 is not essential in dentinogenesis during development but is possibly involved in the regulation of continuous dentinogenesis in the incisors at an advanced age.

Early Diagnosis on Oral and Potentially Oral Malignant Lesions: A Systematic Review on the VELscope® Fluorescence Method

The fluorescence method is an innovative technique used by pathologists for examining body mucosa, and for the abnormalities tissue screening, potentially leading to the earlier discovery of pre-cancer, cancer or other disease processes. The early detection is one of the best mechanisms for enabling treatment success, increasing survival rates and maintaining a high quality of life. The purpose of this review is to evaluate the clinical efficiency of this diagnostic tool applied to the oral cavity (VELscope^®). A literature systematic review has been performed. The initial research provided 53 results after applying the inclusion and exclusion criteria, and after a manual screening of the abstracts by the authors, only 25 results were eligible for review. The results and data contained in all the researches, no older than 10 years, were manually evaluated, and provided useful information on this diagnostic method. The VELscope^® mean value about sensitivity and specificity resulted of 70.19% and 65.95%, respectively, by results analysis, but despite this some studies disagree about its clinical effectiveness, and this diagnostic method is still much debated in scientific and clinical medical literature. Surely being able to have efficient and effective tools from this point of view could help the clinician in the diagnosis, and also make timelier the pharmacological or surgical therapy, improving the quality of life of the patient, and in some cases guaranteeing a longer survival term.

Method for diagnosing neoplastic lesions by quantitative fluorescence value

Fluorescence visualization devices (FVs) are useful for detecting malignant lesions because of their simple and noninvasive application. However, their quantitative application has been challenging. This study aimed to quantitatively and statistically evaluate the change in fluorescence intensity (FI) during the progression from normal epithelium to squamous cell carcinoma using a reproducible animal tongue carcinogenesis model. To establish this model, rats were treated with 50 ppm 4-Nitroquinoline 1-oxide (4NQO) in their drinking water for 10, 15, and 20 weeks. After 4NQO administration, each rat tongue was evaluated by gross observation, histology, and FI measurements. Fluorescence images were captured by FV, and ImageJ was used to measure FI, which was analyzed quantitatively and statistically. The establishment of a reproducible tumor progression model was confirmed, showing precancerous lesions (low-grade dysplasia [LGD]), early cancers (high-grade dysplasia/carcinoma in situ [HGD/CIS]), and advanced cancers (Cancer). This carcinogenesis model was quantitatively evaluated by FI. The FI of LGD stage was 54.6, which was highest intensity of all groups. Subsequently, the HGD/CIS and Cancer stages showed decreased FI (HGD/CIS: 46.1, Cancer: 49.1) and manifested as dark spots. This result indicates that FI had more variation and a wider range with increasing tumor progression. We demonstrated that FI migration and an uneven distribution are consistent with tumor progression. Since each step of tumor progression occurs reproducibly in this animal model, statistical evaluation was possible. In addition, tumor progression can be monitored by this new FI analysis method in humans.

An Overview on Current Non-invasive Diagnostic Devices in Oral Oncology

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy, and despite advances in cancer therapies, the overall 5-year survival rate has remained below 50% over the past decades. OSCC is typically preceded by potentially malignant disorders (PMD), but distinguishing high-risk from low-risk PMD is challenging. In the last years, several diagnostic methods as light-based detection systems (LBDS) have been proposed to facilitate the detection of OSCC and PMD. Furthermore, the recent evolution of nanotechnology may provide new opportunities to detect PMD and OSCC at an early stage. Indeed, several preclinical studies showed the potential of nanotechnology to enhance diagnostic accuracy. For these reasons, it is fundamental to conduct studies to evaluate the efficacy of nanotechnology implementation in LBDS. The aim of this article is to review the current literature on LBDS and to provide a summary of the sensitivity and specificity of each technique, and possible future applications of nanotechnologies. The LBDS showed great potential for screening and monitoring oral lesions, but there are several factors that hinder an extensive use of these devices. These devices seem to be useful in assessing lesion margins that must be biopsied. However, to date, conventional oral examination, and tissue biopsy remain the gold standard for OSCC diagnosis. The use of nanotechnologies could be the next step in the evolution of LBDS, thus providing devices that can help clinicians to detect and better monitor oral lesions.

The luminance ratio of autofluorescence in a xenograft mouse model is stable through tumor growth stages

The aim of this research was to investigate the value of autofluorescence imaging of oral cancer across different stages of tumor growth, to assist in detecting tumors. A xenograft mouse model was created with human oral squamous cell carcinoma cell line HSC-3 being subcutaneously inoculated into nude mice. Tumor imaging was performed with an autofluorescence imaging method (Illumiscan®) using the luminance ratio, which was defined as the luminance of the tumor site over the luminance of normal skin tissue normalized to a value of 1.0. This luminance ratio was continuously observed postinoculation. Tumor and normal skin tissues were harvested, and differences in the concentrations of flavin adenine dinucleotide and nicotinamide adenine dinucleotide were examined. The luminance ratio of the tumor sites was 0.85 ± 0.05, and there was no significant change in the ratio over time, even if the tumor proliferated and expanded. Furthermore, flavin adenine dinucleotide and nicotinamide adenine dinucleotide were significantly lower in tumor tissue than in normal skin tissue. A luminance ratio under 0.90 indicates a high possibility of tumor, irrespective of the tumor growth stage. However, this cutoff value was determined using a xenograft mouse model and therefore requires further validation before being used in clinical diagnosis.

Clinical Application of the IllumiScan Fluorescence Visualization Device in Detecting Oral Mucosal Lesions

Objective: Fluorescence visualization devices are screening devices that can be used to examine lesions of the oral mucosa non-invasively. We observed oral squamous cell carcinoma (OSCC) and leukoplakia using the IllumiScan (Shofu, Kyoto, Japan) fluorescence visualization device and examined its usefulness and characteristics.

Methods: We investigated 31 OSCC and nine leukoplakia in patients who were examined using the IllumiScan and treated in our department from January 2017 to February 2018. Images taken with the IllumiScan were analyzed using image analysis software. We also examined the lesions using narrowband imaging (NBI). Additionally, the IllumiScan and NBI images and the non-stained areas of iodine staining method (IOM) were visually evaluated.

Results: The average luminance of OSCC in the keratinized mucosa was significantly lower than that of OSCC in non-keratinized mucosa. The average luminance of OSCC was significantly lower than that of leukoplakia. Even in keratinized mucosa where IOM is impossible to use, the OSCC lesion exhibited fluorescence visualization loss.

Conclusion: The application of the fluorescence visualization device to the oral mucosa may be useful for distinguishing between cancer and normal areas and can be used to detect OSCC in the keratinized mucosa. The use of the IllumiScan in combination with other conventional screening methods may lead to a better diagnosis.